The concept of light boxes or light tubes wherein a light source located at one end of an elongated fixture transmits light radially outward along the entire length of the elongated fixture is known in the art. One of the difficulties with the use of light boxes as overhead lights in applications as ambulances is that the light boxes generally do not have sufficient, uniform, light output to satisfy minimum Federal lighting requirements for ambulances. The present invention is directed to an improved light box that uses high light reflecting films such as prismatic films. The use of prismatic films or light guides that have substantially 100% total reflection that are located on the interior of the light guide is discussed in the Paper by Stevan G. Saxe titled Progress in the Development of Prism Light Guides A second paper from 3M Center in St. Paul, Minn. describes the 3M Brand Scotchlamp Film that can be used either as a light conduit or as a continuous glowing luminaire. In the 3M light distribution system a light source is located at one end of a light box with a reflective mirror located at the opposite end. The interior of the light box is covered with a conventional white light reflecting material such as white paper or white paint. Inside the light box there is a cylinder of the high light reflecting film that has substantially 100% total internal reflection. This product is sometimes also referred to in the industry as a prismatic film. The use of a high light reflecting film that has substantially 100% total internal light reflection in a light source is described by 3M as being analogous to a perforated garden hose that fills up with water under pressure, with the pressure forcing the water out the perforations along the garden hose. With a tube of the high light reflective film the light is continually reflected inward however, since even the high light reflective films are not 100% perfect, some light does leak out through the film. It is this light that leaks out through the high light reflective film that provides the illumination to the surrounding area that makes light box useful as a light source. The present invention utilizes the existing high light reflective film to produce an improved light output through the arrangement of the high light reflective film and the light reflecting surfaces to provides a low cost light box that provides a uniform cool light output over the entire length of the light box.